Field of the Disclosure
The present disclosure is directed to imager systems, and, more specifically, to an apparatus, system and method for a manufactured imager system.
Description of the Background
Electronic imager systems are used, for example, in photo-imaging applications. An imager may be formed from charge-coupled-devices (CCD) or complementary metal oxide semiconductor (CMOS) devices. An imager may contain many thousands of transistors which, in essence, define pseudo-“pixels” arranged in an array.
By way of example, mobile device cameras, such as smartphone cameras, typically are based upon a small photosensor integrated circuit imager (e.g., an OmniVision OVT14825 CMOS image sensor) that integrates with the hardware and software of the mobile device. The image sensors are typically configured with a “screen” formed of pseudo-“pixels” in the form of photosites, and at least one port for communicating with, for example, other device elements connected via a substrate, such as one found on a processor, on which the image sensor (also referred to herein as an “imager”) resides. The imager may generally includes millions of such light-sensitive photosites. The photosites each optically receive some portion of that which is in the view field of at least one lens placed “atop” the photosites to form an imager system, and hence the lens is communicatively associated with the imager in the imager system to produce the recorded images.
Imagers may be provided as various structures. For example, separate imager dies may be formed, such as part of chip scale packaging (CSP) or as part of through-silicon via (TSV) modules. Regardless of the particular construction of the imager, however, the aforementioned lens is generally useful to focus an image upon the “pixels” of the imager. The lens may generally be separately manufactured through well-known processes, such as casting, injection molding, machining, or the like, and is thereafter positioned at a precise focal distance from the surface of the imager die in order to produce an acceptably sharp image. In the case of imagers used in devices such as mobile phones, the lens of such an imager system may be set to a fixed, optical focal position.
By way of further example, conventional fabrication techniques for mobile device imager systems may use a lens barrel or a fixed stand-off to achieve a desired focal length, or an attachment of the lens using active alignment, such as aided by an adhesive and/or using in situ monitoring of the optical image quality. Thus, in the case of imager systems used in devices such as mobile phones, the lens may typically be set to a fixed optically optimal focal position, which may not provide the desired optical images or resolution, or aligned using complex manufacturing steps, each of which may encounter relatively high costs, manufacturing complexity and low yield.
Additionally, optical tolerances for imager systems have generally become smaller, increasing the level of precision required for positioning the lens relative to the imager. In many devices, the lens, lens array and/or lens system may typically be separately and discretely manufactured and installed directly on the imager in a separate assembly process, which means a method of optically corresponding the lens to the imager is required. Accordingly, conventional fabrication techniques use the aforementioned active alignment or mechanical adjustment techniques to obtain the desired or acceptable image quality from the imager system.
More specifically, traditional imager systems, such as camera modules, are typically assembled passively, i.e., without utilizing information from the camera module components. Active alignment techniques allowed for determination of the optimal relative positioning of camera module components based on the functional output of one or more of the camera module components being assembled. For example, since positional feedback of the camera module components could thus be based on, for example, the output of the imager during manufacturing assembly, rather than solely with reference to the physical geometries of the components being assembled, the individual component tolerances and overall imager tolerance became less critical in the manufacturing process.
However, conventional lens barrels, lens standoffs or actively aligned lenses can increase cost, and may not be easily adjusted to achieve desired image quality. Further, the foregoing techniques may require a high degree of complicated and expensive automation. Moreover, these techniques do not allow for compensation for a wide range of tolerance issues within the lens, imager or any additional cover glass associated with the imager system. This may be, in part, for example, due to the adjustment to achieve the correct focal length being made separately and/or uses the afore-discussed complex automation, and/or in part because the use of additional materials, such as adhesives, and additional process steps, such as in the case of active alignment, involve discrete manufacturing of parts and devices, shipments of parts or devices, and/or discrete positioning, verification and monitoring of these other parts, devices and techniques, which, of course, all have individual tolerances. Yet further, in the aforementioned cases there is often an interfering interface layer or layers, such as air, that may increase the diffraction of light or that may implicate the use of other complex injection molding processes, and which thus further contribute to unintended variations in and from tolerances.
The importance of the issues above is evident notwithstanding that, once an image is captured by an assembled imager system, the communicative connection to the device's processing system allows for processing of the image received at the imager. This is because such processing may typically be suitable only for improving an image of acceptable quality at capture, and hence is not well adapted to “fix” a poor image that suffers from, for example, poor optical quality at capture due to the elements of the imager system itself.
Thus, a need exists for an apparatus, system and method that may avoid discrete lens manufacturing for an imager system, and may eliminate the need for complicated automation to assemble the lens, such as in active alignment.